The present invention relates to a card edge connector, and more particularly to a card edge connector for a circuit board or a circuit card.
In personal computers, card edge connectors are provided for receipt of circuit boards or circuit cards. The card edge connector has a slot and a pair of eject levers which are provided at opposite ends of the slot, so that the circuit board or the circuit card is inserted into the slot to attach the circuit board or the circuit card to the card edge connector and the circuit board or the circuit card is fixed by closing the eject levers. The eject levers are opened to remove the circuit board or the circuit card from the card edge connector.
FIG. 1 is a schematic perspective view illustrative of a conventional card edge connector with eject levers. A conventional card edge connector 5 has a slot 51 for insertion of a circuit board or a circuit card and a pair of right and left eject levers 52r and 52l which are provided at opposite ends of the slot 51. The slot 51 has keys 53 for prevention of an insertion in incorrect direction of the circuit board or the circuit card into the slot 51. The keys 53 are positioned in left half side of the slot 51. The right and left eject levers 52r and 52l extend upwardly from the opposite ends of the slot 51, wherein lower portions of the right and left eject levers 52r and 52l are pivotally connected to the opposite ends of the slot 51, so that the right and left eject levers 52r and 52l are permitted to rotate around the lower portions thereof. Activation heads of the right and left eject levers 52r and 52l extend in inside directions so that the right and left eject levers 52r and 52l rotate to close and stand upright to engage the heads of the right and left eject levers 52r and 52l into recessed portions provided on opposite sides of the circuit board or the circuit card to attach or fix the circuit board or the circuit card to the card edge connector. When the right and left eject levers 52r and 52l are opened to disengage the heads of the right and left eject levers 52r and 52l from the recessed portions of the circuit board or the circuit card in order to detach the circuit board or the circuit card from the card edge connector.
In order to satisfy the requirement for a possible reduction of the manufacturing cost, it is preferable that the right and left eject levers 52r and 52l are symmetrical in shape with each other, for which reason the conventional card edge connector 5 has the symmetrically shaped right and left eject levers 52r and 52l.
As described above, the keys 53 are provided in order to prevent the insertion in incorrect direction of the circuit board or the circuit card into the slot 51. The positions of the keys 53 are near the left end of the slot 51, whilst the circuit board or the circuit card also has a bottom side which has slits positioned near the left side. The keys 53 of the card edge connector 5 correspond in position to the slits of the circuit board or the circuit card. For those reasons, if the circuit board or the circuit card are about to be inserted into the slot 51, however, in the incorrect direction so that the right side and the left side of the circuit board or the circuit card are reverse to those of the card edge connector 5, then the slits of the circuit board or the circuit card do not correspond in position to the keys 53, whereby the insertion in incorrect direction of the circuit board or the circuit card into the card edge connector 5 is prevented.
The above conventional card edge connector has the following problems. In order to insert the circuit board or the circuit card into the slot 51 of the card edge connector 5, a relatively large force, for example, about 10 kg is necessary. This means that if the insertion direction of the circuit board or the circuit card into the slot 51 of the card edge connector 5 is incorrect, then almost the same force as about 10 kg is applied to the keys 53 and the bottom portion of the circuit board or the circuit card, whereby the keys 53 and the bottom portion of the circuit board or the circuit card might be damaged.
In the above circumstances, it had been required to develop a novel card edge connector free from the above problem.